The applicant is a clinical neuropsychologist with graduate training in neuropsychology and postdoctoral training in neuropharmacology and positron emission tomography (PET). The goal of this career development award is to integrate and advance these two areas of interest to answer questions about the neuropharmacological and neurophysiological basis of cognitive dysfunction in movement disorders such as Parkinson's disease (PD). This award will provide the applicant with training in the technical and theoretical issues related to using cognitive and pharmacological activation techniques in functional magnetic resonance imaging (fMRI). Long-term objectives are to address questions about the neural basis of cognitive dysfunction in movement disorders related to dopaminergic and/or basal ganglia dysfunction, such as PD, Tourette's syndrome and Huntington's disease. In addition, questions about the effects of dopaminergic treatments for these and other disorders (e.g. dystonia) on cognitive and neurophysiological functioning are also of interest. Cognitive dysfunction in these diseases, either due to the disease process itself or its treatments, can be limiting and disabling. Understanding the neurophysiologic basis for these symptoms may aid in assessing the effectiveness of current treatments or in developing better treatments. During the award period, the applicant will develop expertise in the use of fMRI, cognitive and neuropharmacological techniques to study these disorders, and will continue to hone her clinical skills in the neuropsychological assessment of movement disorders. The applicant will apply these new techniques to investigate the role of dopamine in working memory. The specific aims of the proposed studies are to test the hypothesis that 1) PD affects prefrontal cortex involvement in working memory and 2) dopaminergic modulation of working memory primarily occurs due to changes in lateral prefrontal cortical activity. To test these hypotheses, the applicant will first perform a behavioral study examining the effects of a steady-state infusion of levodopa, a dopamine precursor, on verbal and spatial working memory in PD patients and controls. The results of this study will then guide the choices of working memory tasks for an fMRl study. Subjects will be asked to perform working memory tasks before and during a steady-state infusion of levodopa. Modulation of the lateral prefrontal cortex is predicted during levodopa infusion. The degree of modulation is predicted to depend on baseline dopaminergic status (PD vs control) and the degree of memory load (low vs high).